Radiofrequency ablation of haemodynamically unstable ventricular tachycardia after myocardial infarction

OBJECTIVE—To determine whether radiofrequency (RF) ablation might have a role in haemodynamically unstable ventricular tachycardia.
METHODS—10 patients with a history of ventricular tachycardia producing haemodynamic collapse in whom drug treatment had failed and device therapy was rejected underwent RF ablation of ventricular tachycardia in sinus rhythm. The arrhythmogenic zone was defined on the basis of abnormal systolic movement, the presence of fragmentation (low amplitude, prolonged multiphasic electrograms), and pace mapping. RF lesions were delivered in power mode in linear fashion within the defined arrhythmogenic zone.
RESULTS—Success (no ventricular tachycardia inducible postablation or at retest) was achieved in six patients, possible success (a different ventricular tachycardia inducible at more aggressive stimulation) in three. In one patient, the procedure was abandoned because of poor catheter stability. There were no clinical events during a mean (SD) follow up period of 23 (10) months in any of the nine patients defined as definite or possible successes.
CONCLUSIONS—RF ablation for addressing haemodynamically unstable ventricular tachycardia opens the door for the wider use of catheter ablation for treating this arrhythmia.


Keywords: tachycardia; catheter ablation; sudden deat

PCR Based Diagnosis of 21-hydroxylase Gene Defects in Slovak Patients with Congenital Adrenal Hyperplasia

Objective. To analyse 21-hydroxylase gene for 8 most common mutations in patients with saltwasting type of congenital adrenal hyperplasia. Methods. Allele specific PCR performed on 8 salt-wasting CAH patients and their 23 healthy relatives. Results. Two patients were homozygous for 8 bp deletion in exon 3, while 6 patients were homozygous for intron 2 splice mutation. Mutant allele for splice mutation was find also in both parents of patients with this type of mutation. Conclusions. These preliminary results show that only two mutations, 8 bp deletion in exon 3 and splice mutation in intron 2, were present in this group of Slovak patients with salt-wasting type of congenital adrenal hyperplasia

Nanoscaled Al-AlN composites consolidated by equal channel angular pressing (ECAP) of partially in situ nitrided Al powder

Nanoscaled aluminium nitride (AlN) reinforced aluminium matrix composites were fabricated using a novel approach where powder mixtures of Al+Mg+Sn were partially in situ nitrided in flowing nitrogen followed by consolidation through equal channel angular pressing (ECAP). The resulting composites contain up to 23.8. vol% of AlN with relative density >98%. The microstructure shows two distinctively different alternate lamellar regions. One is the Al matrix free of AlN and the other is composed of nanoscaled AlN embedded in the Al matrix. The Al-AlN composites fabricated this way exhibited attractive properties, including thermal stability up to 450 °C, high compressive strength, high Young's modulus and low coefficient of thermal expansion. The presence of nanoscaled AlN reduced the thermal conductivity of the composites compared to the high thermal conductivity of Al-AlN composites prepared by metal infiltration techniques